Terminal member for liquid cooled rotor winding



June 7, 1966 E. MEYER 3,255,298

TERMINAL MEMBER FOR LIQUID COOLED ROTOR WINDING Filed Nov. 8, 1963 INVENTOR Eugen Meyer BY/WWJVLWWXQ 1mm ATTORNEYS United States Patent 3,255,298 TERMINAL MEMBER FOR LIQUID COOLED ROTOR WINDING Eugen Meyer, Baden, Aargau, Switzerland, assignor to Aktiengesellschaft Brown, Boveri 8t Cie, Baden, Switzerland, a joint-stock company Filed Nov. 8, 1963, Ser. No. 322,488 Claims priority, application Switzerland, Dec. 14, 1962, 14,713/ 62 3 Claims. (Cl. 1748) The present invention relates to apparatus for supplying a liquid coolant to hollow conductor structures for electric machinery. An example of such liquid cooling is the hollow conductor structure for the stationary, stator winding of turbo-generators wherein conventional tubing is used for the terminal or connecting piece to .convey the liquid coolant to and from the hollow conductor structure.

In the case of liquid-cooled rotor windings, it is notvery practical to use ordinary tubing to convey the liquid to and from the hollow conductor structure since very high centrifugal forces are often created dependent upon the speed and dimensions of the rotor and these lead to creation of very high internal pressures ranging from 100 to 150 atmospheres. Thus for application of liquid cooling to the hollow conductors of a rotor it is necessary to employ an extraordinarily mechanically strong construction but which, at the same time, must exhibit a certain amount of flexibility due to the heat expansion which takes place under continued operation of the machine and moreover, it must be electrically insulated.

The purpose of the invention is therefore to provide an improved construction for a hollow terminal or connecting piece through which the liquid coolant can be passed into and out of the hollow conductor structure, and particularly for application to the rotary field structure of synchronous machines with salient poles, such as hydroelectric generating apparatus.

In accordance with the invention, the terminal or connecting piece is characterized by a flexible part including at least one helically wound spring made from me'tallic tubing so as to establish a fluid passageway therethrough from one end to the other, the metallic tubing being secured at its opposite ends to tubular end fittings, the interiors of which communicate with the interior of the metallic tubing from which the spring is made, one of these tubular end fittings being attached to one end of a tubular metallically reinforced electrically insulating memher and in fluid communication therewith.

The helically coiled hollow spring may be composed of one spring, or a plurality of helical springs which may be arranged either in parallel or concentrically, one within the other. The electrically insulating part features a glass fiber sleeve surrounded by a tubular part made from a casting resin and which is reinforced mechanically by a metallic insert.

One suitable embodiment of the invention will now be described and is illustrated in the accompanying drawing whoih is a longitudinal view, one half of'which is in section and the other in elevation.

With reference now to the drawing, the terminal piece for connection to the lead-in or lead-out end of the hollow conductor coil on the field pole of the rotor structure, the latter not being illustrated, is seen to be comprised of a flexible part 1 which is secured to a rigid, electrically insulating part 2. The flexible part 1 is comprised of one or more helically wound springs made from metal- I lie tubing so as to establish a fluid passageway through the metal of the spring itself from one end to the other for the fluid coolant. In the illustrated embodiment two Ice such springs are used and these are arranged in parallel so to speak. Alternatively, a plurality of such springs may be arranged concentrically one within the other. The number of springs, and the number of turns for each spring will very, dependent upon the elasticity required for the particular application.

The electrically insulating part 2 is comprised of an inner glass fiber sleeve 3 surrounded by a tubular housing 4 made from a suitable casting resin and which is mechanically reinforced by means of one or more metallic inserts. In the illustrated embodiment, these inserts shown at 5 and 5' are each seen to be comprised of a an annular base portion into which a corresponding end of the glass fiber sleeve 3 is fitted and an annular sleeve portion 5a which is cast-in with the resin body 4.

The upper end of the helically wound tubular spring 1 is secured fast by welding within an annular recess 6a in the lower face of a tubular end fitting 6 and the-latter is provided with an upwardly facing peripheral flange 6b which is welded to the peripheral part of the reinforcing insert 5'. The lower end of tubular spring lis similarly secured fast by welding within an annular recess 6a in the upper face of another tubular end fitting 6 andthe latter is provided with a downwardly facing peripheral flange 6b which is welded to a peripheral part of a tubular coupling or union 7. A similar tubular coupling or union 8 is provided at the opposite end of the terminal piece and one part of the union 8 is welded to the base portion of the upper metallic reinforcing insert 5.

Thus the improved flexible and composite terminal structure for the rotor winding is comprised of the hollow unions 7 and 8, the tubular end fittings 6 and 6', the helically wound metallic tubing 1, and the tubular metallically reinforced electrical insulating member 2. The

flow path of liquid coolant through the composite terminal structure from one end to the other is established through the interior of tubular union 8, thence through the interior of tubular insulating member 2 and the interior of tubular end fitting 6'. The fluid coolant now enters one end of the metallic tubing from which the spring 1 is formed, the fluid flowing through the metal of the spring itself rather than through the interior of the helix. The fluid exists from the other end of the metallic tubing and then flows through the interiors of the other end fitting 6 and union 7.

In cases where very high internal pressures will not be created, it is possible to eliminate the inner glass fiber sleeve 3 and use a casting resin having a higher mechanical strength for the insulating part 4.

In conclusion, it is desired to point out that while the improved construction for the tubular, terminal piece isv vided with liquid cooled rotor windings.

I claim: 1 1. A composite tubular terminal piece for liquid cooled rotor windings of electrical machines, which comprises a flexible part constituted by a helical spring made from metallic tubing such as to establish a fluid passageway through the metal of the spring itself from one thereof to the other, a tubular fitting at each end of said helical spring, each said fitting being connected to the corresponding end of said helical spring so as to establish a fluid communication between the interior of said fitting and said fluid passageway through said spring, a tubular metallically reinforced electrically insulating member having one end thereof connected to one of said tubular end fittings and in fluid communication therewith, and a further tubular fitting connected to the opposite end of said tubular insulating member and in fluid communication References Cited by the Examiner therewith.

2. A terminal piece for liquid cooled rotor windings UNITED T E PATENTS of electrical machines as defined in claim 1 wherein said 1,208,938 12/1916 Fmch 174 69 flexible part is comprised of two parallel wound hollow 5 2542841 2/1951 Rqberds 174-15 X helical springs 3,163,209 12/1964 Shmn 16583 3. A terminal piece for liquid cooled rotor windings FOREIGN PATENTS of electrical machines as defined in claim 1 wherein said electrical insulating part is comprised of a glass fiber sleeve surrounded by a tubular part made from a casting resin and which is mechanically reinforced by a metallic 10 ROBERT SCHAEFER Primary Examiner insert. LARAMIE E. ASKIN, Examiner.

236,471 7/1945 Switzerland. 

1. A COMPOSITE TUBULAR TERMINAL PIECE FOR LIQUID COOLED ROTOR WINDINGS OF ELECTRICAL MACHINES, WHICH COMPRISES A FLEXIBLE PART CONSTITUTED BY A HELICAL SPRING MADE FROM METALLIC TUBING SUCH AS TO ESTABLISH A FLUID PASSAGEWAY THROUGH THE METAL OF THE SPRING ITSELF FROM ONE THEREOF TO THE OTHER, A TUBULAR FITTING AT EACH END OF SAID HELICAL SPRING, EACH SAID FITTING BEING CONNECTED TO THE CORRESPONDING END OF SAID HELICAL SPRING SO AS TO ESTABLISH A FLUID COMMUNICATION BETWEEN THE INTERIOR OF SAID FITTING AND SAID FLUID PASSAGEWAY THROUGH SAID SPRING, A TUBULAR METALLICALLY REINFORCED ELECTRICALLY INSULATING MEMBER HAVING ONE END THEREOF CONNECTED TO ONE OF SAID TUBULAR END FITTINGS AND IN FLUID COMMUNICATION THEREWITH, AND A FURTHER TUBULAR FITTING CONNECTED TO THE OPPOSITE END OF A SAID 